在此論文中,我們選擇Motorola Lab所提出的Beacon_Tx_Offset方 式作為beacon conflict的解決方案,並參考TDMA頻道存取的方式來規劃Beacon_Tx_Offset的使用,透過上述兩種方式的結合以避免相鄰節點間發生beacon conflict而造成後續無法傳輸資料。 While establishing the wireless personal area network that bases on IEEE 802.15.4 LR-WPANs communication protocol and with the self-configurable characteristic, every node in the network must be able to automatically establish and maintain its link capacity. Therefore, the synchronization between nodes is an important mechanism.
IEEE 802.15.4 LR-WPANs specification is the communication protocol designed for a wireless personal area network with short-range and low data rate RF transmissions, it support the operation of beacon to provide some advantages, like network synchronization, QoS and low power consumption. At present, there is still ambiguous in IEEE 802.15.4 LR-WPANs specification for the beacon operating. Therefore, there will be a beacon conflict problem in the complex topology network, it will cause nodes to lose the synchronization with its parent node and be unable to transmit. So, the establishment of a method to avoid beacon conflict is an important issue.
In this paper, we select the Beacon_Tx_Offset method purposed by Motorola Lab as the beacon conflict solution and refer TDMA channel access method to schedule the use of Beacon_Tx_Offset. Through the two method described above, we could avoid the beacon conflict between neighbor nodes and following incapacity of data transmission.